The present invention relates to a winged needle assembly used for intravenous infusion or catheter placement. More particularly, the invention relates to an assembly for reliably interlocking the wings of the needle assembly during insertion of the needle into the vein of a patient.
Winged infusion sets makes venipuncture easier as suggested by U.S. Pat. No. 3,064,648 to Bujan, hereby incorporated by reference herein. The flexible plastic wings fold or are pinched together for firm needle control during venipuncture and fold flat after needle insertion to provide a firm anchor for taping. The short needle shaft minimizes the possibility of needle movement within the vein.
U.S. Pat. Nos. 4,300,553, 4,388,074 and 4,389,210, each of which is hereby incorporated by reference herein, disclose needle-inside catheter placement assemblies which capture a needle in the winged hub assembly to assist in puncturing a vein and placing a catheter therein. The needle is then withdrawn.
Of prime concern in both procedures is the insertion of the needle into the vein. Care must be taken not to further cut or puncture the sides of the vein. Any movement of the sharp needle tip may cause damage to the patient's vein.
The flexible wings of known winged needle assemblies are capable of flexing so that both wings can be firmly grasped between the thumb and forefinger. However the smooth surfaces of the plastic wings which are pressed together allows the wings to slid against each other. This relative movement of the wings is transferred to the needle shaft and may cause the sharp needle tip to pivot or move. If the needle is in the vein when this movement occurs, the vein walls can be damaged.
The above relative movement of the wings has been partially addressed by the inclusion of mating means such as a pin or knob and a receiving cavity or hole on opposed wings so as to index the two wings to each other. When the wings are flexed together, the pin should register into the hole and secure the two wings into relative position.
However, it has been observed that many times the pin does not find or register with the hole and initially sits on the smooth surface of the wing. Often the pin slips into the hole as the needle is being inserted into the vein, which causes the tip of the needle to move correspondingly. Thus, the above solution does not fully prevent needle movement if the wings are initially misaligned.